Simon was put in charge of commencing hostilities.
Simon was charged with commencing hostilities.
Simon was made responsible for commencing hostilities.
Simon was given the task/job/role of commencing hostilities.
Simon was attributed the mission of commencing hostilities.
Simon was given responsibility for commencing/the opening of hostilities.

Sorry if I repeated anything but this sounds like a job for the good ol' scatter-bomb technique!

In addition to rebellious schoolchildren, one can in a business situation be in charge of a thing, as in: Mary is in charge of the ABC project or [SIZE=-1]The lunatics are now in charge of the asylum.[/SIZE]

But for an action, we generally use Xis responsible for doing something.